BQ24610: Boost from VBAT damage MOSFET and BQ24610

Please use fresh units and show scope capture at the battery insertion. Probe at VBAT1, VSW .

When adapter is not present, plugging in VBAT should bq24610 should not switch. Therefore, it is very unlikely to have 29V at SW node with 12V battery hotplug in.

Sorry click on the bottom by mistake.
Looking at your schematic, a 22uF cap needs to be added at the VBAT1 node close to the battery. However, this should not cause the voltage spike. We have customer using this part for 5cells and 6 cells for a long time but have not had hot plug in damage on our part.. Please submit the IC for FA so we can get information on which pin is been damaged on the bq24610.

Hi Sir,

We are remove the Q40's R736 & C579, the VSW never boost to 28~32V to damage BQ24610 & CSD87330.

Why this boost is Through R736 & C579?

As I know, TI BQ24610EVM is suggest the Q1 & Q2 on input side.

if we want to cost down one MOSFET, How to design? similar BQ24170 datasheet page 28 Q4 is OK? 

Ch3= U2 Pin3

Ch4= U2 Pin5

I am assuming the input source is still not connected, correct?

Could you please also probe V_ADP when plugging battery to see if it ever comes up? 

Hi Sir,

We are try to remove BQ24610EVM Q5, but we are see the VSW have boost 18V voltage & current probe measure 66,4A.

if we add Q5 same condition on customer PCB, then boost issue solve Rise is Smooth.

if this application only 5~6 charger docking board not have system side on PCB, then Q5 is must? or change to Schottky or diode? or any suggest share for me?

The first peak current is to charge up the cap on the board. The second peak is what we should look at.

Without Q5 current directly goes through inductor to charge the input caps thus you will see the VSW overshoot. 

If there is no system, you can use shottcky diode instead.

Hi Sir,

Thank you very much.
if customer want to use the shottcky diode,
then we need to concern about Forward Current or Forward Surge Current? how many current value is Safety?

Hugo